<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <script type="text/javascript" src="js/jquery-1.12.4.js"></script>
    <script type="text/javascript">
        $(function () {
            $('#btn').click(function () {
                $('.box').animate({
                    'width': 600,

                }, 1000, function () {
                    $('.box').animate({
                        "height": 400,
                    }, 1000, function () {
                        $('.box').animate({
                            'opacity': 0,
                        }, 1000)
                    })
                });
            });

            $('#btn2').click(function () {
                $('.box2').stop().animate({'width':'+=100'})

            });



        });
    </script>
    <style type="text/css">
        .box {
            width: 100px;
            height: 100px;
            background-color: gold;
        }

        .box2 {
            width: 100px;
            height: 100px;
            background-color: gold;
        }
    </style>
    <title>Document</title>
</head>

<body>
    <input type="button" value="改变大小" id="btn">
    <div class="box"></div>
    <br />
    <br />
    <br />
    <input type="button" value="改变" id="btn2">
    <div class="box2"></div>

</body>

</html>